Epidemiologic studies suggest that Trichomonas vaginalis is associated with a 2- to 4-fold increased risk of HIV transmission, contributing to health disparities. Thus, control of trichomonosis may be an effective means of reducing HIV transmission risk worldwide. T. vaginalis causes vaginitis in women and is associated with adverse outcomes in pregnancy. In addition, trichomonosis is linked to cervical cancer. In men, infection causes non-gonococeal non-chlamydiat urethritis and may play a role in prostate cancer. Despite this impact to public health, fundamental aspects of parasite biology and host immunology remain unknown, such as our understanding of the urogenital-mucosal antibody (Ab) response to T. vaginalis. The goal of this project is to take advantage of the common mucosal immune system and examine the mucosal Ab using the saliva of patients. The objectives are to understand the mucosal Ab response in the patient in order to develop prevention and control strategies. The rationale is that effective control of STIs requires a complete picture of the host mucosal Ab response, and vaginal fluids of patients cannot provide this information. A knowledge base of the mucosal Ab response to trichomonosis may be the basis of a future vaccine and provide reagents for a point of care, noninvasive diagnostic for both male and female. The hypothesis is that the common mucosal immune system results in the presence in saliva of Ab to T. vaginalis proteins similar to that found in vaginal secretions. This proposal reflects our combined strengths of basic and applied research to the study of Trichomonas vaginalis biology and has three aims. Aim 1 will examine the mucosal Ab response to T. vaginalis protein antigens. Aim 2 will isolate unique T. vaginalis proteins reactive with saliva Ab from patients. Aim 3 will identify trichomonad recombinant proteins for development of a noninvasive saliva diagnostic for trichomonosis. A result from this work will be the isolation of novel genes and proteins as Ivirulence factors. The of subtractive cDNA and to and isolate proteins for a saliva Ab diagnostic are innovative. The major significance of this work will be our knowledge of the nature and extent of the mucosal Ab response to T. vaginalis and reduction of STI transmission risk worldwide.